import html2Canvas from 'html2canvas'
import JsPDF from 'jspdf'
export default {
    install(Vue, options) {
        Vue.prototype.getPdf = function (dom, title) {
            html2Canvas(document.querySelector(`#${dom}`), {
                allowTaint: true,
                taintTest: false,
                useCORS: true,
                //width:960,
                //height:5072,
                dpi: window.devicePixelRatio * 4, //将分辨率提高到特定的DPI 提高四倍
                scale: 4 //按比例增加分辨率 
            }).then(function (canvas) {
                let contentWidth = canvas.width
                let contentHeight = canvas.height
                let pageHeight = contentWidth / 592.28 * 841.89
                let leftHeight = contentHeight
                let position = 0
                let imgWidth = 595.28
                let imgHeight = 592.28 / contentWidth * contentHeight
                let pageData = canvas.toDataURL('image/jpeg', 1.0)
                let PDF = new JsPDF('', 'pt', 'a4')

                // 分页
                if (leftHeight < pageHeight) {
                    PDF.addImage(pageData, 'JPEG', 0, 0, imgWidth, imgHeight)
                } else {
                    while (leftHeight > 0) {
                        PDF.addImage(pageData, 'JPEG', 0, position, imgWidth, imgHeight)
                        leftHeight -= pageHeight
                        position -= 841.89
                        if (leftHeight > 0) {
                            PDF.addPage()
                        }
                    }
                }
                PDF.save(title + '.pdf')
            })
        }
    }
}

